Modular surgical training system

ABSTRACT

A modular surgical training system for training in surgical interventions with real surgical instruments includes a reusable, energy supplying base module, and a regenerable training module which reproduces or has anatomical structures and can hold at least one consumable medium (for example, bodily fluids). The training module and the base module are detachably connected to one another via a combination interface, and pneumatic and/or mechanical and/or electric energy can be transmitted from the base module to the training module and/or electric signals can be transmitted between base module and training module via the combination interface. The base module and training module include conveying elements detachably connected via the combination interface, and at least one consumable medium can be conveyed into the anatomical structures by the conveying elements.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a national stage filing under section 371 ofInternational Application No. PCT/EP2014/074934, filed on Nov. 18, 2014,and published in German on May 28, 2015, as WO 2015/075038 A1 and claimspriority of German applications no. 10 2013 112 746.0 and no. 10 2013112 745.2, both filed on Nov. 19, 2013, the entire disclosure of theseapplications being hereby incorporated herein by reference.

BACKGROUND ART

The invention relates to a modular surgical training system for trainingin surgical interventions using real surgical instruments.

Surgical interventions relate to the treatment, i.e., the therapy, ofdiseases and injuries by direct, manual or instrumental action on thebody of the patient, wherein these surgical interventions are adequatelyreferred to as operation or in short OPs. Operations are known both fromhuman medicine and also from veterinary medicine.

For the purpose of practical learning, repeated practice, and forperfecting surgical techniques, a great variety of training systems areknown, which differ considerably with regard to their claim to realisticsimulation of the actual surgical environment. In addition to entirelycomputer-based virtual training systems such as those offered, forexample, by the company Industrial Virtual Reality Inc., other trainingsystems are known, in which the surgical intervention is practiced on amore or less detailed simulation of an anatomical structure.

These simulated anatomical structures are usually plastic models thatcan have greatly differing features in terms of their complexity andrealistic simulation. In addition to solid bone structures, they containmainly resilient materials for the representation of human tissue. Toachieve the most realistic simulation possible, the focus is primarilyon the haptic properties of the anatomical structure, in particular, ofthe different tissue types such as, for example, bones, vessels ornerves, during the interaction with the surgical instruments held by thepracticing operator. During the training, the anatomical structure usedis used-up by mechanical treatment such as, for example, cutting,milling or the like, so that it needs to be replaced before the nexttraining session.

Systems for reproducing bodily functions such as, for example, asimulated cardiac circulation system with pulse, blood pressure but alsoother bodily fluids can be added to these simulated anatomicalstructures themselves. The simulation of these bodily functionsincreases the degree of detail of the haptic simulation for the personin training, for example, by simulation of the pressure of thecerebrospinal fluid. Moreover, it is known that bleeding, for example,is simulated by way of filled capsules that are caused to burst, or byway of devices for generating large amounts of blood, as occurs, forexample, as a result of severed limbs or arterial injuries.

Furthermore, it is known to reproduce bodily fluids by media such as,for example, fake blood, in order to approximate the color, consistencyand external appearance of actual blood as closely as possible. For thegeneration of a flow or a pressure increase of the corresponding bodilyfluids, pumps, primarily peristaltic pumps, and/or valves as well ascorresponding lines are used. The peristaltic pumps, also referred to ashose pumps, used here are associated with dead times in the conveyance,due primarily to the principle of operation. The media used for thetraining have to be refilled or replaced before the next trainingsession. This harbors a number of different disadvantages. Thus, whenrefilling the media, sufficient venting of the conveyance system mustalways be ensured; in addition, after a reservoir container for thesemedia has been used repeatedly, deposits and encrustations can occur,which in turn lead to sticking and/or clogging.

This results, therefore, in time consuming and expensive cleaning work.

In a real OP, in the general case, there is stress on sensitive tissues,the at-risk structures, that can cause postoperative complications inhuman patients. Typical stress types on at-risk structures such asnerves and vessels that occur during OPs are compression (squeezing,compressive stress) and traction (elongation, tensile stress). For thequantitative evaluation of the surgical interventions for training, itis therefore known to use sensors, in particular, pressure sensors andstrain gauges. Since the sensors used are located directly on theanatomical structure, they too have to be exchanged before each newtraining session along with the anatomical structure, which againresults in added costs.

There are known surgical training systems that combine individualaspects of the described aspects, such as the reproduction of ananatomical structure, the reproduction of various bodily fluids or theuse of a sensor system.

Thus, US 2009/0246747 A1 discloses a training system that reproduces theinside of a human or animal body with all the important organs. Thetraining system includes the reproduction of the cardiac circulationsystem, wherein the heart is reproduced by a peristaltic pump. The largevessels such as the aorta are reproduced by hoses, wherein the internalpressure of the hoses can be measured by means of pressure sensors, orthe volume flow of the medium reproducing the blood can be measured bymeans of flow meters. Reproduced organs can have channels for thereproduction of the vessels of the organ. Thus, in one design, a vesselrupture of a kidney is reproduced, wherein the medium conveyed by theperistaltic pump exits the vessels in large amounts. If the structure ofindividual organs has been changed by the training session, for example,by the use of a scalpel, the entire organ is exchanged.

This training system has several disadvantages. After completion of atraining session, for example, an operation on a kidney, large parts ofthe training system can be soiled by exiting fake blood, as a result ofwhich these parts have to be subjected to a thorough time-consumingcleaning. In addition, the reservoir containers of the used-up mediahave to be refilled again. The used-up anatomical structures, possiblyincluding the corresponding sensors, have to be replaced and connectedagain to the other organs or vessels. Overall, this involves a very highexpenditure in terms of time and personnel, but in the end a very highfinancial expenditure. In addition, the training system is not availableat that time.

Moreover, from WO 2009/067778 A1 a modular training system is known forpracticing operations on and/or in the human skull. The training systemis provided, for example, for operations for placing an external drainin order to lower the pressure within a ventricle filled withcerebrospinal fluid. For this purpose, the training system comprises abase module and a training module. The training module comprises thereproduced anatomical structure in the form of the ventricle, whereinthe ventricle is formed as a latex balloon and filled with water. Forthe generation of a realistic ventricular internal pressure, the basemodule comprises a pressure generator, which is formed by a column ofliquid. The hydrostatic pressure of the column of liquid acts on asecond balloon which is arranged on the base module. If training moduleand base module are connected to one another, then the second balloon isin an operative connection with a latex balloon. Using a scale that isarranged on the column of liquid, the pressure exerted on the ventricleby the person in training can be quantitatively determined as well.

The disadvantage of this system is that the simulation of bleeding iscompletely dispensed with. In addition, due to the special design of thebase station, the base station is suitable only for simulatingoperations on and/or in the skull. There is no provision for training onother anatomical structures, as a result of which the field of use isvery limited. Furthermore, the pressure generator with the liquidlocated therein needs to be maintained regularly, since, for example,due to evaporation, liquid can escape, as a result of which thehydrostatic pressure of the column of liquid can vary from one trainingsession to the other. As a result, a new calibration of the pressuregenerator is needed, which in turn is associated with a time and costexpenditure.

An object of the present invention therefore consists in providing amodular surgical training system which avoids the disadvantages of theprior art and which can be put into operation and returned to a stateready for use by a user within a short period of time without trainedpersonnel and without the user in the process coming into contact withconsumable liquids or other liquids, and which is low maintenance, doesnot require calibration by the user, and is flexible, i.e., suitable fortraining in a great variety of surgical interventions.

BRIEF SUMMARY OF THE INVENTION

Therefore, a modular surgical training system is proposed, comprising areusable, energy supplying base module and a regenerable training modulewhich reproduces or has anatomical structures and can hold at least oneconsumable medium, and which, in particular, is itself not supplied withenergy. Here, the training module and the base module are detachablyconnected to one another via a combination interface. Via thecombination interface, pneumatic and/or mechanical and/or electricenergy can be transmitted from the base module to the training moduleand/or electric signals can be transmitted between base module andtraining module. The base module and the training module compriseconveying means which are detachably connected via the combinationinterface, wherein, at least one consumable medium can be conveyed intothe anatomical structures and/or a pressure can be built up in theanatomical structure by the conveying means.

As a rule, in the present description of the invention, reference ismade to artificial simulation materials or artificial anatomicalstructures, even if they are not explicitly identified as such. However,it is also possible to use true anatomical structures.

An essential advantage of the present invention is the modular design ofthe training system in the form of a base module and a training module.Materials that are used-up during training, so-called consumablematerials such as, for example, anatomical structures or bodily fluidssimulated by at least one consumable medium, are associated with thetraining module. Reusable expensive components such as, for example,pneumatic, electric and/or mechanical actuators, electronic components,or else a torso, for example, for realistic embedding of the anatomicalstructures, are associated with the base module.

Base module and training module are detachably connected via acombination interface, for example, by a locking mechanism. Therefore,the training system according to the invention is very user friendly andinexpensive. This is achieved in that the base station, together withthe above-described expensive components, can normally remain with theuser of the training system, while the used-up training module can beremoved and under some circumstances returned to the manufacturer forregeneration, i.e., in order to refill the at least one consumablemedium and possibly for aeration, and in order to replace the anatomicalstructures after the mechanical treatment by the training surgeon.Accordingly, a plurality of unused training modules can be kept onreserve, which, after completion of a training session, are connected bythe user simply and rapidly via the combination interface to the basestation, in order to carry out the next training session. Support fromspecially trained personnel is not needed; instead, the users themselvescan put the training system into operation. Therefore, setup times forthe preparation of the next training session are considerably shortenedby the modular design according to the invention.

In addition, training modules in each case can also hold differentanatomical structures, so that the training system can be used in a veryflexible manner and is not limited to a single anatomical area such asthe human skull, for example.

An additional advantage according to the invention consists in that theat least one consumable medium is not transferred through thecombination interface. As a result, soiling of the training system isavoided, since the at least one consumable medium remains only on or inthe training module to be exchanged. No consumable medium conveying hoseconnections to be disconnected are needed, which would soil the trainingsystem additionally. Therefore, time consuming cleaning work can bedispensed with.

Moreover, it is essential for the invention that base module andtraining module comprise conveying means that can be detachablyconnected via the combination interface. While active components of theconveying means are arranged in the reusable base module, the passivecomponents are arranged in the training module. Thus, the energyprovided by the active components via the combination interface can betransmitted to the passive components, as a result of which the at leastone consumable medium can be conveyed into the anatomical structures.According to the invention, consumable media can be conveyed so thatthey exit from the anatomical structures, for example, in the form ofbleeding, or so that they reproduce the internal pressure of ananatomical structure, for example, the cerebrospinal fluid pressure ofthe dura mater, more precisely the dural sac and the associated nerveroots, without exiting in the process.

By means of the conveying means, at least one simulated bodily fluid canbe metered during the training into the site, for example, in the formof bleeding. The metering of the bleeding into the site increases therealism of the training session many times over, since it is only as aresult of the bleeding that a typical OP situation is generated. Thebleeding thus creates a permanent visual obstruction. The bleeding mustbe continually suctioned off by the person in training, in order to beable to perform the actual OP steps within the brief period of time ofunobstructed view. This generates realistic work courses, since it putsthe person in training under time pressure in addition to forcing theperson in training to use one hand for holding the suctioning device.

For the disconnection of the active components of the base module fromthe passive components of the training module via the combinationinterface, it is possible to provide, in a design according to theinvention, that the conveying means in the base station comprise atleast one air compressor generating pneumatic energy in the form ofpressurized air. The air compressor itself is driven, for example, byelectric means, wherein, for this purpose, the base module is suppliedwith electric energy via an external energy source.

Moreover, it is appropriate for the conveying means in the trainingmodule to comprise at least one pressurized volume which holdspressurized air. Via the combination interface, the generated pneumaticenergy can be transmitted from the base module to the training module.Moreover, it is possible to provide that the training module comprisesat least one consumable media volume which is separated on the mediaside from the pressurized volume and holds a consumable medium. Here,pressurized volume and consumable media volume interact with one anotherin such manner that at least one consumable medium can be conveyed intothe anatomical structures or an internal pressure is generated in atleast one anatomical structure.

According to the invention, as a result of the use of pressurized air asenergy carrier, a media-side separation is made possible, i.e., the atleast one consumable medium is associated only with the training moduleand it does not have to be conveyed via the combination interface. Incontrast to the use of peristaltic pumps, steady conveyance of the atleast one consumable medium can be achieved here, i.e., without the deadtimes in the conveyance that occur typically with peristaltic pumps.Moreover, another disadvantage of peristaltic pumps is that they aredriven by volume flow and thus, in contrast to pressure-driven pumps,the conveyance pressure is not defined, which can, for example, lead toa pressure increase in case of clogging.

In another embodiment of the training system according to the invention,at least two consumable media can be held by the training module,wherein the first consumable medium can be conveyed through at least oneexit site of the anatomical structures, and the internal pressure of atleast a section of the anatomical structures can be reproduced by meansof the second consumable medium. As a result, the realism of thetraining system is further increased, for example, by forming the firstconsumable medium as fake blood and the second consumable medium as amedium that simulates the cerebrospinal fluid. Additional consumablemedia for stimulating other bodily fluids can be provided according tothe invention.

Moreover, it is advantageous that the first consumable medium and thesecond consumable medium each form a separate consumable medium volume,which in each case interacts with a corresponding pressurized volume.

According to the invention, the first consumable medium, which is formedby fake blood, for example, can also be conveyed through more than oneexit site of the anatomical structures. Thus, exit sites can be arrangedin a plurality of different positions on the anatomical structure,which, however, can, but do not need to, be supplied from the sameconsumable media volume. Therefore, different bleeding situations can besimulated thereby. An essential advantage of the modular design hereagain is that, when starting up or regenerating the training system, theuser does not have to connect each exit site separately to theconsumable media volume. Instead, the anatomical structures, the atleast one consumable medium, and the connection thereof to theanatomical structures can already be preassembled in the training moduleand needs only to be connected to the base station. As a result,failures such as those that occur due to wear, for example, afterfrequent use, can be prevented. Pressure losses due to leaking caused bywear can be prevented.

In addition, it is advantageous that the base module and the trainingmodule comprise control means which are detachably connected via thecombination interface and can control at least one volume flow. Here, itis advantageous that the control means can control at least one volumeflow of the at least one consumable medium. If, as in another design,several exit sites for a consumable medium are provided on theanatomical structures, then at least one of the volume flows to the exitsites can be controlled by the control means. If several volume flowsare controllable, the realism of the training system can be furtherincreased, since different amounts of the at least one consumable mediumcan exit at different exit sites. Thus it is possible to simulate lightto intense arterial bleeding and to practice handling such bleeding.

While active components of the control means are arranged in thereusable base module, the passive components are arranged in thetraining module. Thus, the energy provided by the active components canbe transferred via the combination interface to the passive components,as a result of which the at least one volume flow is controllable.

In one embodiment according to the invention, the control means in thebase station comprise at least one constriction hose valve actuator fordisconnecting the active components of the base module from the passivecomponents of the training module via the combination interface. Theconstriction hose valve actuator itself is driven by electric means, forexample, wherein, for this purpose, the base module is supplied withelectric energy via an external energy source.

Therefore, it is advantageous if the control means in the trainingmodule comprises at least one self-blocking constriction hose valve. Viathe combination interface, the mechanical energy, which is generated bythe constriction hose valve actuator, for example, can be transferredfrom the base module to the training module, and the self-blockingconstriction hose valve is opened. The constriction hose valve can herebe arranged so that a connection element, for example, a hose,connecting the consumable media volume to an exit site, can constrict ina continuously controllable manner. Due to the self-blocking of theconstriction hose valve, it is possible to prevent the at least oneconsumable medium from exiting through the exit site on the anatomicalstructures when the training module is not connected to the base module.In this way, the training module can be transported in such a mannerthat no additional consumable media exit and soil the training module.In the same way, it is conceivable to use self-opening valves or acombination of self-blocking and self-opening valves.

In order to give the persons in training a feeling for the consequencesof their handling steps and in order to alert them, if required, byacoustic, visual and/or tactile means to their mistakes resulting, forexample, from excessively high intraoperative stresses, it isadvantageous that the base module comprises a sensor module thatmeasures at least one physical variable. However, it is possible herethat, for example, measurement transducers are optionally present in thetraining module. Here, it is advantageous that sensor module andtraining module comprise measurement means that can be detachablyconnected via the combination interface. Due to the division of themeasurement means into the base module and the training module, themanufacturing and operating costs of the training system can be loweredfurther. Via the combination interface, the energy and/or electricsignals provided by the sensor module for controlling the measurementmeans can be transmitted from the base module to the training module.

Conversely, acquired physical variables can be transmitted from trainingmodule to sensor module by electric signals. The sensor module can inturn transmit the measured physical variables in the form of electricsignals to an external evaluation unit, outside of the base module.

Appropriately, the measurement means in the training module comprises atleast one ultrasound transmitter and a corresponding ultrasoundreceiver. For this purpose, for example, ultrasound capsules can beused, which convert electric signals into acoustic pressure waves. Inthe case of the use of an ultrasound transmitter (transmitter) and acorresponding ultrasound receiver (receiver), the so-called two-capsulemeasurement principle can be used. Here, an ultrasound capsule astransmitter generates an acoustic pressure pulse in the ultrasoundfrequency range, which is transmitted along into a measurement medium,passes through said medium, and is converted again at the other end byan ultrasound capsule as receiver into an electric signal. However,according to the invention, a one-capsule measurement principle can alsobe used. Here, an ultrasound capsule functions as transmitter andreceiver. Then, it is no longer the transmitted pulse that is measured,but rather reflections that occur due to the transmission behavior.

Therefore, it is appropriate that the measurement means in the trainingmodule comprise at least one air-filled connection means. Thisconnection means can be formed, for example, as a silicone hose, so thatit is resiliently deformable.

Moreover, the first end of the connection means can also be connected tothe ultrasound transmitter and the second end of the connection means isconnected to the ultrasound receiver, so that the two-capsulemeasurement principle can be used. For the one-capsule measurementprinciple, one end of the air-filled connection element can be closed inan air-tight manner, wherein the other end of the air-filled connectionelement can be connected to an ultrasound capsule which functions astransmitter and receiver. Independently of which measurement principleis used, the air-filled connection element forms the measurement medium.The incorporation of air in the measurement medium makes it possible touse low-frequency ultrasound, which reduces the cost for sensors andelectronics man times over compared to the high frequency systemsthereof.

It is appropriate that the connection means is disposed on or in theanatomical structures, wherein the anatomical structures and theconnection means interact with one another, and a deformation of theanatomical structure can be measured by a traction and/or a compressionof the connection means. The simultaneous measurement of compression andtraction (elongation) by the measurement means using a combinationmeasurement method is essential to the invention. Thus, there is no needto use multiple measurement means and measurement methods. Severalconnection means can also be provided in order to be able to measure thecompression and the traction of areas of the anatomical structures thatare spaced apart from one another.

In the integration of a part of the measurement means in the trainingmodule, it is advantageous if this part of the measurement means can beprepared, for example, calibrated in such a manner that the user of thetraining system is relieved of this time consuming work.

In principle, according to the invention, other measurement means, forexample, measurement means with sensors, can also be provided for theacquisition of other physical variables such as elongation, pressure,temperature or the like.

According to the invention, the base module can also comprise acontroller module that processes an electric signal and that can beconnected to a user interface for the operation of the training system.The controller module can be suitable, for example, for controlling theconveying means and/or the control means and/or the measurement meansvia electric signals, and for receiving electric signals, for example,as measured physical variables of the sensor module. Individual electricsignals can be exchanged with a user interface, which can be connectedto the controller module by wireless link or by cable. For example, inthis manner, direct visual and/or tactile and/or acoustic feedback canbe given to the person in training during the training session.Moreover, by means of the user interface, other training parameters suchas, for example, the amount and duration of bleeding or other events canbe set.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

Below, the invention is to be explained in further detail with referenceto exemplary embodiments. In the associated drawings

FIG. 1 shows an isometric view of a base module of a training systemaccording to the invention,

FIG. 2 shows an isometric view of the base module and a training moduleconnected thereto of the same training system according to theinvention,

FIG. 3 shows a cutaway side view through the base module and thetraining module with depicted conveying means of the same trainingsystem according to the invention,

FIG. 4 shows a cutaway side view through the base module and thetraining module with depicted control means of the same training systemaccording to the invention,

FIG. 5 shows an arrangement of measurement means on anatomicalstructures of the training module,

FIG. 6 shows a diagrammatic representation of the one-capsulemeasurement principle,

FIG. 7a shows a diagrammatic representation of the two-capsulemeasurement principle,

FIG. 7b shows a qualitative representation of a measured signal thatchanges as a function of the deformation of the measurement means,

FIG. 8 shows a diagrammatic representation of different coupling piecesof the measurement means, and

FIG. 9 shows an arrangement of the measurement means on the anatomicalstructures of the training module with labeling of the force action onthe measurement means.

DETAILED DESCRIPTION

FIGS. 1 to 9 show a modular surgical training system according to theinvention for training in surgical interventions. The modular surgicaltraining system according to the invention is designed in a particularlyuser-friendly and cost-optimized manner due to its modular construction.

FIG. 1 and FIG. 2 illustrate the advantages of the modular construction.FIG. 1 shows an isometric view of a base module 1 of the training systemaccording to the invention. The base module 1 comprises a base plate 11which, however, is not shown in FIG. 2. The base plate 11 can bedetachably connected to a structure, which is not shown, so that aslipping of the base module 1 is prevented. Arranged on the base plate11 are both an actuator module 12 on the left side of FIG. 1 and alocking mechanism 13 on the right side of FIG. 1. In the actuator module12, reusable expensive components of the conveying means 6, of thecontrol means 7 and of the measurement means 8 are arranged. Othercomponents of these conveying means 6, control means 7 and measurementmeans 8 are arranged in the training module 2. This also includesmaterials that are used during a training session, so-called consumablematerials such as, for example, anatomical structures 3 or bodily fluidssimulated by at least one consumable medium 4, which, however, is notshown in FIGS. 1 and 2.

Moreover, the base module 1 can have a torso, which is not shown,arranged on the base module 1 and/or on another structure in such amanner that the anatomical structures 3 are placed on theircorresponding site of the human body, in order to simulate in thismanner the difficulties of access to the anatomical structures 3. Theanatomical structures 3 of this exemplary embodiment represent an areaof the human lumbar vertebral column. Since the anatomical structures 3are arranged exchangeably on the training module 2, other areas of thehuman body but also the animal body can also be reproduced. As a result,the modular training system is designed in a particularly flexiblemanner.

A combination interface 5 is provided for the connection of the trainingmodule 2 to the base module 1. In this exemplary embodiment, thecombination interface 5 comprises connections that are not labeledfurther, wherein, in each case, connections for the transmission ofpneumatic, mechanical and electric energy from the base module 1 to thetraining module 2 are provided. Furthermore, connections are provided bymeans of which the electric signals can be exchanged between base module1 and training module 2. The designation combination interface 5 ischosen here, since different energies or energy carriers can betransmitted via a common, combined interface (combination interface 5).Via this interface, media such as fluids, for example, can also betransferred. The training module 2 comprises connections correspondingto the base module 1, so that the base module 1 and training module 2can be detachably connected to one another via the combination interface5. To ensure the connection, a locking mechanism 13 is provided, whichis formed as a clamping lever.

FIG. 3 to FIG. 5 diagrammatically depict the arrangement of theconveying means 6, control means 7 and measurement means 8, not shown ordepicted only partially in FIGS. 1 and 2, on base module 1 and trainingmodule 2. Due to the modular construction of the training system, bothbase module 1 and also training module 2 each have components of theconveying means 6, control means 7 and measurement means 8.

First, the formation of the conveying means 6 representeddiagrammatically in FIG. 3 will be described. In principle, theconveying means 6 are provided in order to convey at least oneconsumable medium 4 into the anatomical structures 3. In this exemplaryembodiment, which, as explained above, reproduces an area of the humanlumbar vertebral column, it is provided to convey two consumable media 4into anatomical structures 3. The first consumable medium 4 heresimulates blood 42. The blood 42 is conveyed into the anatomicalstructures 3 in such a manner that it exits from the anatomicalstructures 3 through exit sites 31. The second consumable medium 4simulates cerebrospinal fluid 41. The cerebrospinal fluid 41 is conveyedinto the anatomical structures 3 in such a manner that it simulates theinternal pressure of the dura mater or of the individual nerve roots,which are reproduced by the anatomical structures 3. In this regard,this exemplary embodiment of the modular training system differs fromthe prior art, since two different consumable media 4 are used.

In the cutaway view according to FIG. 3, the actuator module 12 of thebase module 1 is depicted on the left side. An air compressor 61 isarranged in the actuator module 12, wherein the air compressor 61 issupplied with electric energy via an external voltage source, which isnot shown. For this purpose, the base module 1 comprises a connection,not shown, which can be connected to this voltage source. The electricenergy of this external voltage source is also used for supplying thecontrol means 7, the measurement means 8, but also other means that arenot shown. The air compressor 61 generates pneumatic energy in the formof air pressure.

In each case, the air compressor 61 is connected via a pair of hoseconnections that are not identified further as well as via plugconnectors 66 on the combination interface 5, to a pressurized volume 62arranged in the training module 2; here, the arrows in FIG. 3 indicatethe connection diagrammatically. A corresponding consumable mediumvolume 63 is associated with each pressurized volume 62. Blood 42 isarranged in one consumable medium volume 63, and cerebrospinal fluid 41is arranged in the other consumable medium volume 63. Pressurized volume62 and consumable media volume 63 are formed as pressure pouches and areproduced from plastic, for example. In each case, a correspondingpressurized volume 62 and consumable media volume 63 pair is arrangedbetween a pair of plates 64. Wherein pairs of these plates 64 can alsocomprise common plates 64. Due to the limited space between the plates64, a volume increase of the pressurized volume 62, which is caused bythe elevated air pressure, is transmitted to the consumable media volume63, as a result of which the latter is compressed. However, since theconsumable medium 4 is essentially incompressible, it gives way to thevolume increase of the pressurized volume 62. The blood 42 can beconveyed to the exit sites 31 via corresponding hose connections, whichare not depicted but instead merely indicated by arrows. All the exitsites 31 can here be supplied with blood 42 from a consumable mediavolume 63. For this purpose, a distributor 65 is provided, which dividesthe blood 42 into individual volume flows 43. Via corresponding hoseconnections that are not identified further, the cerebrospinal fluid 41can be conveyed into the dura mater and the nerve roots simulated by theanatomical structures 3. However, in the process, the cerebrospinalfluid 41 does not exit the anatomical structures 3, but rather simulatesthe internal pressure of the anatomical structures 3. Fluid will exit,however, if the anatomical structure is injured, for example, if aperforation of the dura mater is produced.

An essential advantage of the present invention consists in that theconsumable media 4 are not transferred via the combination interface 5.The used-up consumable media 4 and the used-up anatomical structures 3remain exclusively in the training module 2, which, after the trainingsession, is separated from the base module 1 after opening the lockingmechanism 13. The training module 2 can then be returned, for example,by mail, to the manufacturer, who subjects it to regeneration in orderto replace the anatomical structures 3 and also the consumable media 4.As a result, the base module 1 is protected against soiling. Immediatelyafter a completed training session, the training module 2 can be removedand replaced with a new, unused training module 2. No traininginterruptions result due to a time-consuming regeneration that affectsthe entire training system, since the base station 1 can be reconnectedimmediately to the new, unused training module 2 to continue thetraining.

For the metering itself of the conveyed consumable media 4, controlmeans 7 are provided, which are represented in the cutaway side view ofFIG. 4. In the actuator module 12, two hose valve constriction actuators71 are arranged for this purpose, wherein the hose valve constrictionactuators 71 are supplied with electric energy via the above-mentionedexternal voltage source, which is not shown. In another design of theinvention, more than two hose valve constriction actuators 71 can bearranged in the actuator module 12. In each case, it is advantageous toassociate a hose valve constriction actuator 71 with each volume flow 43formed by a consumable medium 4.

By means of mechanical connections that are not identified further,mechanical energy can be transmitted in the form of a changeableoperating displacement of the hose valve constriction actuators 71 viathe combination interface 5. Here it is also possible to control theflow not only via the operating displacements but also via a pulsewidth-modulated pulse operation (between the on/off states). The actualsetting of the respective volume flows 43 to the exit sites 31 occurs inthe training module 2 by means of constriction hose valves 72 arrangedthere. The constriction hose valves 72 are designed to be self-blockingand/or self-opening and can be opened by a pressure force applied to thehose valve constriction valve 72. The pressure force is provided here bythe hose valve constriction actuator 71 and transmitted in the form ofmechanical energy via the combination interface site 5. In the presentexemplary embodiment, two constriction hose valves 72 are provided, sothat the volume flows 43 of the two exit sites 31 can be set separately.

In principle, the conveyance of the consumable media 4 can be decoupledfrom the metering of the consumable media 4 due to the arrangement ofconveying means 6 and control means 7. As a result, cross influencing ofthe volume flows 43 of different exit sites 31 can be reduced bychanging the position of the constriction hose valves 72. Since theconstriction hose valves 72 are arranged in the training module 2, theexpensive adjustment thereof by the user can moreover be dispensed with,and the adjustment can be carried out instead by the manufacturer whenthe training module 2 is regenerated. This also applies to the aerationof the conveying means 6, which can already be carried out during theregeneration. Due to the arrangement of the consumable media 4 in thetraining module 2, it is possible to dispense with a consumable mediatank according to the prior art. As a result, the risk of clogging orsticking of the conveying means 6 with consumable media 4 can be nearlyruled out, since the consumable media conveying components of theconveying means 6 are arranged in the training module 2, and the latteris regenerated. In other words, the user does not have to deal with therefilling of the consumable media 4. Here, it is also advantageous thatthe user of the training system does not have to carry out a timeconsuming startup of the training system, since the conveying means 6are already connected to the exit sites 31.

In order to give the persons in training a feeling for the consequencesof their handling steps and in order to alert them as required byacoustic, visual and/or tactile means to their mistakes resulting, forexample, from excessively high intraoperative stresses, it isadvantageous that the base module 1 comprises at least one sensor module81 that measures at least one physical variable. The sensor module 81 isthe part of the measurement means 8 that is arranged in the base station1, wherein the sensor module 81 can transmit electric energy via thecombination interface 5 to the part of the measurement means 8 arrangedin the training module 2. For the transmission of, for example, controlsignals or measurement signals, the measurement means 8 can exchangeelectric signals via the combination interface 5.

As already explained, typical stress types on at-risk structures, suchas nerves and vessels, that occur during the OP are compression 821(squeezing, compressive stress) and traction 822 (elongation, tensilestress). Resilient tissues react highly variably to stresses, since thedeformation as a consequence of an applied force depends on volume,material properties, external shape and embedding.

Compression 821 and traction 822 can occur anywhere on the anatomicalstructures 3. In another exemplary embodiment, for the local measurementof these stresses, it is possible to use one-dimensional ormulti-dimensional strain gauges or also directly one-dimensional ormulti-dimensional load cells. However, this embodiment is very expensivein terms of cost and material, since a plurality of individual straingauges or load cells have to be applied on or in the anatomicalstructures 3.

On the other hand, ultrasound in the pulse method with the use of ameasurement head for transmitting and receiving is widely employed inthe field of medical imaging methods and therapies, but also, forexample, in the field of materials testing. The basis is the measurementof reflected ultrasound waves and the evaluation of the transit time ofthe signals, in order to show inner organs or defects in components, forexample. The disadvantage is the high ultrasound frequency that isneeded for a sufficiently high resolution and precision. Also, thesesystems need continual adjustment by specialized personnel only.

The measurement means 8 of this exemplary embodiment comprise the sensormodule 81 in the base module 1 as well as an ultrasound transmitter 83,an ultrasound receiver 84, and an air-filled connection means 82 whichat the same time forms the measurement medium 82, in the training module2. In another exemplary embodiment, no medium 82 is provided. However,with the use of the measurement medium 82, integration of themeasurement means 8 in the anatomical structures 3 can be facilitated.

Interaction of the anatomical structures 3, which are represented atleast partially in FIG. 5 and which comprise a dura mater with nerveroots and also vertebral bodies, with the measurement medium 82, forexample, by the interaction of the person in training with theanatomical structures 3, causes a change in the geometric properties ofthe measurement medium 82. For the acquisition of this change,ultrasound capsules, which convert electric signals into acousticultrasound waves, are placed at open ends of the air-filled measurementmedium 82. FIG. 5 shows two possible configurations for the formation ofthe measurement means 8. For this purpose, the measurement medium 82 isintegrated in portions of the dura mater and in a nerve root of avertebra, i.e., in the interior of the anatomical structure 3 filledwith cerebrospinal fluid 41.

In the two-capsule measurement principle, which is depicted in the leftarea of FIG. 5, an ultrasound capsule as ultrasound transmitter 83generates an ultrasound wave in the ultrasound frequency range, which istransmitted along into the measurement medium 82, travels through themeasurement medium 82, and is converted into an electric signal again atthe other end by an ultrasound capsule as ultrasound receiver 84.

In the one-capsule principle, which is depicted in the right area ofFIG. 5, an ultrasound capsule functions as ultrasound transceiver unit85, wherein it is not the transmitted pulse that is measured, but ratherthe reflections thereof that occur due to the transmission behavior.

Ultrasound capsules, in general, have a cross section that is greaterthan that of the measurement medium 82. This is the case particularly ifthe measurement medium 82 is dimensioned very small to be arranged insmall anatomical structures 3. Thus, a coupling has to be provided, inorder to arrange the ultrasound capsules 83, 84, 85 at the ends of themeasurement medium 82, and in order to couple the ultrasound waves fromthe large cross section of the ultrasound capsules 83, 84, 85 to thesmall cross section of the measurement medium 82, or in order todecouple them again from the small cross section to the large crosssection. Accordingly, suitable coupling media 86 are used. The specialfeature of these coupling media 86 is that they have a predeterminedcross section profile as extension of the measurement medium 82.

Different formations of the coupling media are represented as examplesone below the other, in FIG. 8, wherein these coupling media in eachcase have different advantages and disadvantages. Thus, the linearfunnel represented at the very top in FIG. 8 is suitable fortransmitting a very large amount of energy from the ultrasoundtransmitter 83 or from the ultrasound transceiver unit 85 to themeasurement medium 82. The same applies in the reverse direction, frommeasurement medium 82 to the ultrasound receiver 84 or to the ultrasoundtransceiver unit 85. The exponential funnel depicted second from the topin FIG. 8 has a hyperbolic transition, which adapts the cross section ofthe measurement medium 82 to the ultrasound capsules in such a mannerthat no measurable reflections occur on the coupling medium 86. Thirdfrom the top in FIG. 8, a coupling medium 86 with a sound damper isrepresented, wherein the cross section transition is formed by anindentation. The sound damper damps the entering ultrasound waves and itleaves only a very small passage free, adapted to the inner diameter ofthe measurement medium 82, for the transition into or out of themeasurement medium 82. As a result, a very smooth ultrasound wave istransmitted into the measurement medium 82. Here, it is advantageousthat the electric signal to be acquired has a very satisfactory signalshape, i.e., a signal shape without much interference. Fourth from thetop in FIG. 8, a wall funnel is represented, which is formedgeometrically like the funnel with sound damper, but which lacks a sounddamper.

For processing the electric signals from and to the ultrasound capsules83, 84, 85, the sensor module 81 comprises analog and digital switchingparts, which are not shown. Via a digital-analog converter, signalshapes for the transmission are produced, amplified and conveyed to theultrasound transmitter 83 or to the ultrasound transceiver unit 85. Viaan analog-digital converter, the received signal of the ultrasoundreceiver 84 or of the ultrasound transceiver unit 85, after filteringand amplification, is converted into digital values in the form ofelectric signals. The processing of these digitized values by aprocessor, which is not shown, is the basis of the calculation of theoriginal stresses due to applied force. For this purpose, the processor,which is not shown, can comprise commands of adaptable software that canbe stored separately in the sensor module 81.

The following is a description in connection with FIG. 6 and FIG. 7a andFIG. 7b of how conclusions regarding the application of force can bedrawn from an action on the anatomical structures 3.

In the case of a propagation of an ultrasound wave in the measurementmedium 82, a change in the acoustic impedances occurs at each change incross section ΔA of the measurement medium 82, resulting in reflections.When the ultrasound wave passes through such a site with a change incross section ΔA, this leads to a change in acoustic impedance and tothe division of the ultrasound wave into a reflected part and atransmitted part, see the ultrasound waves depicted diagrammatically inFIG. 6. The reflected part is reflected to the ultrasound transmitter 83or to the ultrasound transceiver unit 85. The transmitted part maintainsthe direction of the original ultrasound wave. The division of theenergy of the original ultrasound wave is dependent on the value of thechange in cross section ΔA. Without a change in cross section ΔA noreflection occurs; with increasing change in cross section ΔA, theenergy portion of the reflected ultrasound wave increases, and thetransmitted ultrasound wave is damped.

As explained, two measurement principles are distinguished. In thetwo-capsule measurement principle, the transmitted part of theultrasound wave in the original signal is detected and evaluated. Toillustrate the two-capsule measurement principle, FIG. 7a representsfrom top to bottom the undisturbed starting state of the measurementmedium 82, the measurement medium 82 with a change in cross section ΔA,and the measurement medium 82 with a change in length Δ1. In FIG. 7b ,the corresponding electric signals converted by the ultrasound receiver84 are depicted qualitatively, for example, as electric voltage versustime t.

The ultrasound transmitter 83 transmits ultrasound pulses of finitelength at fixed periodic intervals relative to one another. If themeasurement medium 82 is not stressed, the electric signal of theultrasound receiver 84 corresponds to the undisturbed transmittedultrasound wave. The latter is adapted in the non-stressed state to theinput signal range of the analog-digital converter.

In the case of orthogonal stressing, a decrease in the energy of thetransmitted ultrasound pulse due to the change in cross section ΔAoccurs, and thus a decrease in the amplitude of the electric signal incomparison to the original signal without stress occurs. Then, thedifference between the energies is a measure of the change in crosssection ΔA, so that a damping parameter D can be defined:

$D = \frac{E_{1}}{E_{0}}$which is dependent on the measure of the change in cross section ΔA. Thetransmitted ultrasound pulse has energy E₁, and the original ultrasoundpulse without stress has energy E₀.

If the measurement medium 82 is stressed in longitudinal direction, thechange in length Δ1 causes a temporal offset Δt of the transmittedultrasound pulse in the electric signal to be evaluated in comparison tothe original electric signal without stress. By means of this temporaloffset Δt, the change in length Δ1 can be calculated:Δl=c _(L) Δt

wherein c_(L) is the speed of the ultrasound wave in the measurementmedium 82, and is calculated by means of the temperature in the interiorof the measurement medium 82.

The original compressive force F_(K) can be calculated by calibration asa function of the change in length Δ1 and the damping D. The sameapplies to the original, length-changing force F_(T):F _(K) =f ₁(Δl,D), F _(T) =f ₂(Δl,D)

wherein the compressive force F_(K) is dependent mainly on the dampingD, and the length-changing force F_(T) is dependent mainly on the changein length Δ1.

As explained in the case of the one-capsule measurement principle, thereflected part of the wave is detected and evaluated in the outputsignal. The ultrasound wave introduced by the ultrasound transceiverunit 85 is reflected completely at the closed-off end and it moves backto the ultrasound transceiver unit 85, which, as receiver, now convertsthe ultrasound wave again into an electric signal which is the object ofthe evaluation.

If there is no load on the measurement medium 82, the signal isidentical to the one depicted at the top of FIG. 7a and FIG. 7b . Incontrast to the two-capsule principle, the ultrasound wave travels twicethe distance, so that the absolute transit time of the ultrasound wavecorresponds to twice the length of the measurement medium 82.

The force applied in the longitudinal direction of the measurementmedium 82 according to FIG. 7a (bottom) leads to an elongation of themeasurement medium 82, which also leads to a change in transit time, atemporal offset Δt, of the ultrasound wave. The calculations remain thesame.

The orthogonal force application according to FIG. 7a (center) leads toa reflection at the site of the change in cross section ΔA. In contrastto the two-capsule principle, the amplitude of the electric signal ofthe ultrasound transceiver unit 85 increases the stronger thecompressive force application is. Analogously to the two-capsuleprinciple, the damping parameter D can be calculated as:

$D = \frac{E_{0} - E_{1}}{E_{0}}$which is dependent on the change in cross section ΔA. The reflectedultrasound wave has energy E₁, and the original ultrasound wave withoutstress has energy E₀. The advantage of the one-capsule measurementprinciple is that the site of the force application can be determinedvia the transit time of the ultrasound wave.

By means of the damping parameter D and the change in length Δ1, theoriginal forces can be determined in the same way as already describedabove.

In this way, in an additional exemplary embodiment, it is also possiblethat a plurality of connection means, measurement media 82, are arrangedin the anatomical structures 3. FIG. 9 shows such an exemplaryembodiment based on the first exemplary embodiment of FIG. 1 to FIG. 5.The measurement media 82 are arranged, according to FIG. 9, so that ineach case a measurement medium 82 is arranged in a nerve root, wherein,in each case, two nerve roots are associated with a vertebral body. Themeasurement media 82 in turn are arranged within the cerebrospinal fluid41, wherein this cerebrospinal fluid 41 in turn can have a pressurewhich is generated by the corresponding conveying means 6.

Also depicted in FIG. 9 are the compressive force F_(K) to be determinedvia the measurement means 8 and the length-changing force F_(T), forexample, as reaction forces of compression 821 or traction 822. Aparticular advantage of measurement means 8 formed in this manner isthat the acting forces F_(K) and F_(T) can be determined in any positionof the force application on the measurement medium 82. In other words, achange in cross section ΔA and/or a change in length Δ1 can bedetermined integrally over the entire measurement medium 82. Moreover,it is advantageous in measurement means 8 formed in this manner that theacting forces F_(K) and F_(T) can be determined with the same means,i.e., an ultrasound transmitter 83 with a corresponding ultrasoundreceiver 84 or an ultrasound transceiver unit 85.

The training simulator is operated via a user interface, which is notshown, which communicates by wireless link or by cable with a controllermodule, which is not shown, wherein the controller module is arranged onthe base module 1, for example, in the actuator module 12. The userinterface can be formed, for example, as a portable terminal, in theform of a laptop, tablet PC, smartphone or the like.

The user interface is suitable for receiving electric signals providedby the controller module from the conveying means 6, the control means 7and the measurement means 8, and for transmitting electric signals tothe conveying means 6, the control means 7 and the measurement means 8via the controller module. Thus, for example, the pressure level of thepressurized air provided by the air compressor 61 can be set. Moreover,the volume flows 43 of blood 42 to the respective exit sites 31 can beset. In addition, the current pressure of the compressed air and thecurrent volume flows 43 can be depicted both qualitatively andquantitatively. Applications of force by the person in training to theanatomical structures 3, which can be determined by the measurementmeans 8, can also be represented visually as well as acoustically. Thus,feedback on the mechanical stress resulting from their work on theat-risk anatomical structures can be issued instantaneously to theperson in training.

MODULAR SURGICAL TRAINING SYSTEM List of Reference Numerals

-   -   1 Base module    -   11 Base plate    -   12 Actuator module    -   13 Locking mechanism    -   2 Training module    -   3 Anatomic structures    -   31 Exit sites    -   4 Consumable media    -   41 Cerebrospinal fluid, simulated    -   42 Blood, simulated    -   43 Volume flow    -   5 Combination interface    -   6 Conveying means    -   61 Air compressor    -   62 Pressurized volume    -   63 Consumable media volume    -   64 Plate    -   65 Distributor    -   66 Plug connector    -   7 Control means    -   71 Constriction hose valve actuator    -   72 Constriction hose valve    -   8 Measurement means    -   81 Sensor module    -   82 Connection means, measurement medium    -   821 Compression    -   822 Traction    -   83 Ultrasound transmitter    -   84 Ultrasound receiver    -   85 Ultrasound transceiver unit    -   86 Coupling medium    -   ΔA Change in cross section    -   C_(L) Speed of the ultrasound wave    -   Δ1 Change in length    -   Δt Temporal offset    -   D Damping parameter    -   E₀ Energy of the original pulse    -   E₁ Energy of the transmitted pulse    -   F_(K) Compressing force    -   F_(L) Length changing force    -   t Time

The invention claimed is:
 1. A modular surgical training system fortraining surgical interventions, comprising a regenerable trainingmodule reproducing or having anatomical structures and capable ofholding at least one consumable medium, a reusable base module,supplying energy to the training module, wherein the training module andthe base module are detachably connected to one another via acombination interface, and pneumatic and/or mechanical and/or electricenergy can be transmitted from the base module to the training moduleand/or electric signals can be transmitted between the base module andthe training module via the combination interface, wherein the basemodule and the training module comprise conveying means detachablyconnected via the combination interface, and at least one consumablemedium can be conveyed into the anatomical structures by the conveyingmeans, wherein the base module comprises a sensor module that measuresat least one physical variable, wherein the sensor module and thetraining module comprise measurement means detachably connected via thecombination interface, wherein the measurement means in the trainingmodule comprise at least one ultrasound transmitter and at least onecorresponding ultrasound receiver, and wherein the measurement means inthe training module comprise at least one air-filled connection means.2. The modular surgical training system according to claim 1, wherein atleast two consumable media can be held by the training module, wherein afirst consumable medium can be conveyed through at least one exit siteof the anatomical structure, and via the second consumable media, aninternal pressure of at least one section of the anatomical structurescan be reproduced.
 3. The modular surgical training system according toclaim 1, wherein the base module and the training module comprisecontrol means detachably connected via the combination interface and cancontrol at least one volume flow.
 4. The modular surgical trainingsystem according to claim 3, wherein at least one volume flow of the atleast one consumable medium can be controlled by the control means. 5.The modular surgical training system according to claim 3, wherein thecontrol means in the base module comprise at least one constriction hosevalve actuator.
 6. The modular surgical training system according toclaim 3, wherein the control means in the training module comprise atleast one self-blocking and/or self-opening constriction hose valve. 7.The modular surgical training system according to claim 1, wherein afirst end of the connection means is connected to the ultrasoundtransmitter and a second end of the connection means is connected to theultrasound receiver.
 8. The modular surgical training system accordingto claim 1, wherein the connection means is arranged on or in theanatomical structures, wherein the anatomical structures and theconnection means interact with one another, and a deformation of theanatomical structure can be measured by a traction and/or a compressionof the connection means.
 9. The modular surgical training systemaccording to claim 1, wherein the base module comprises a controllermodule which processes electric signals and can be connected to a userinterface for the operation of the training system.
 10. The modularsurgical training system according to claim 1, wherein the conveyingmeans in the base module comprise at least one air compressor generatingpneumatic energy in the form of pressurized air.
 11. The modularsurgical training system according to claim 1, wherein the conveyingmeans in the training module comprise at least one pressurized volumeholding pressurized air and at least one consumable media volumeseparated on a media side from the at least one pressurized volume andholding a consumable medium, wherein the at least one pressurized volumeand the consumable media volume interact with one another, so that atleast one consumable medium can be conveyed into the anatomicalstructures and/or a pressure can be generated in the anatomicalstructure.